Pad conditioner for chemical mechanical polishing

ABSTRACT

A pad conditioner for chemical mechanical polishing includes a dressing component for conditioning a pad and a housing for accommodating the dressing component. The housing includes at least one fluid hole surrounding the dressing component for providing at least a fluid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a polishing pad conditioner forchemical mechanical polishing. More particularly, the present inventionrelates to a polishing pad conditioner that is capable of providing afluid for chemical mechanical polishing.

2. Description of the Prior Art

The chemical mechanical polishing process is currently widely used inthe semiconductor field. In a chemical mechanical polishing process, thepolishing property of the surface of the polishing pad deterioratesafter a period of time because the slurry is not able to evenly disperseon the polishing pad any more. To solve the problem, the polishing padconditioner is employed to condition the polishing pad to restore thepolishing property of the surface of the polishing pad.

The conditioning property of the polishing pad conditioner usuallyresides in the dressing component and nowadays the dressing component ismostly composed of diamonds. Therefore, the conditioning property of thedressing component is key to the process stability and the wafer removalrate. A decent dressing component should meet the followingrequirements: stable wafer removal rate, properly conditioning thepolishing pad, regenerating the conditioning property of the polishingpad and extending the operational life of the polishing pad.

During the chemical mechanical polishing process, slurry is usuallyemployed to facilitate the chemical mechanical polishing. When thepolishing pad conditioner conditions the polishing pad, particlesbrought about from the slurry and from the chemical mechanical polishingprocess may transfer to the dressing component during the conditioningprocess. After a while, the particles crystallize and attach to thedressing component, which shortens the operational life of the dressingcomponent and causes the diamonds to come off the dressing component.Such diamonds will scratch the wafer and cause defects. This is aproblem which needs to be solved.

SUMMARY OF THE INVENTION

The present invention therefore provides a polishing pad conditioner forchemical mechanical polishing. The polishing pad conditioner provides afluid to continuously clean the dressing component for conditioning thepolishing pad to avoid particles and to maintain the conditioningproperty of the dressing component, which can stabilize the waferremoval rate and regenerate the conditioning property of the polishingpad.

The polishing pad conditioner for chemical mechanical polishing of thepresent invention includes a dressing component for conditioning a padand a housing for accommodating the dressing component. The housingincludes at least one fluid hole surrounding the dressing component forproviding at least one fluid.

The present invention again provides a method for polishing a substrate.The method of the present invention first provides a substrate. Then thesubstrate is polished by a polishing tool which is provided with atleast a polishing pad and at least a polishing pad conditioner. Thepolishing pad conditioner includes a dressing component for conditioninga pad and a housing for accommodating the dressing component. Thehousing includes at least one fluid hole surrounding the dressingcomponent for providing at least a fluid.

Because the polishing pad conditioner for chemical mechanical polishingof the present invention includes the fluid hole(s) surrounding thedressing component for providing at least a fluid, the fluid hole(s) mayprovide a fluid to clean the dressing component on the polishing padconditioner for chemical mechanical polishing, which avoids thecrystallization of the particles. This will maintain the conditioningproperty of the dressing component and help to diminish the defects onthe wafer.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 illustrate various embodiments of the polishing padconditioner of the present invention.

FIG. 5 illustrate a chemical mechanical polishing system with multiplepolishing pads.

FIG. 6 illustrate a chemical mechanical polishing system with a singlelarge-sized polishing pad.

FIG. 7 illustrates a linear chemical mechanical polishing system.

DETAILED DESCRIPTION

FIG. 1 illustrates the polishing pad conditioner of the presentinvention for chemical mechanical polishing. The polishing padconditioner 100 of the present invention includes a dressing component110 for conditioning a pad and a housing 120 for accommodating thedressing component 110. The materials for the dressing component 110 andthe housing 120 are known in the field and will not be described indetail. The dressing component 110 may be a diamond bar for example. Thesurface of the dressing component 110 may preferably be embedded withgranules of hardness between 4-10. The granules may be made of SiC,dimond, ZrO₂, Al₂O₃.

In order to clean the dressing component 110 to avoid the accumulationof the slurry and the particles, the housing 120 includes at least onefluid hole 121 surrounding the dressing component 110 for providing atleast one fluid to wash away the slurry and the particles to keep thedressing component 110 clean when the fluid spurts.

The polishing pad conditioner 100 and the dressing component 110illustrated in FIG. 1 are rectangular, but are not limited to this. Forexample, the polishing pad conditioner 100 and the dressing component110 may also be in any shape, such as round or oval, i.e. the disc shapein FIG. 2, or a polygon, such as the triangle in FIG. 3. In addition,the housing 120 of the polishing pad conditioner 100 may include aplurality of parts which can be assembled together. For example, in FIG.2, the housing 120 is composed of two pieces 120A/120B.

The size of the housing 120 depends on the size of the wafers. Forexample, for a system for the 8-inch wafer, the length of the housing120 may be 31-32 cm and the width may be 6-7 cm. Besides, for a systemfor the 12-inch wafer, the size of the housing 120 may be about 70 cm.

Optionally, the fluid supplied by the fluid hole 121 may be liquids suchas water or slurry, or gases such as air or inert gas, or thecombination thereof. For example, the slurry may be supplied during thepolishing process to facilitate the chemical mechanical polishing andensure that the slurry will not dry out on the surface of the dressingcomponent 110 of the polishing pad conditioner 100. Alternatively, watermay be supplied during the conditioning of the polishing pad to cleanthe dressing component 110, or gas may be supplied to clean the dressingcomponent 110. Moreover, there may be at least one fluid channel in thehousing 120 of the polishing pad conditioner 100, such as the fluidchannels 122A/122B illustrated in FIG. 1 to supply each of the fluidholes 121 surrounding the dressing component 110 with a fluid. The fluidchannel(s) and the fluid hole(s) may also be removably attached to thehousing 120 of the polishing pad conditioner 100, for example externallyhung on the housing 120 of the polishing pad conditioner 100.

In order to enhance the fluid to clean the dressing component 110, thelocation of the fluid holes 121 can be optionally arranged so that thefluid may substantially contact the dressing component 110 when spurtingfrom the fluid holes 121 to wash away any slurry, particle or crystalpossibly attached to the dressing component 110.

To keep the dressing component 110 secure in the housing 120, thehousing 120 may further include a slot 123 in a shape corresponding tothe dressing component 110, as shown in FIG. 4, in addition to theconventional screws. The dressing component 110 may engage with the slot123 of the polishing pad conditioner 100 by sliding thereinto to fix arelation position between the dressing component 110 and the housing120. Furthermore, screws may be used to keep the dressing component 110secure in the housing 120 to enhance the performance of the dressingcomponent 110 and the wafer removal rate.

The polishing pad conditioner of the present invention may be employedin various chemical mechanical polishing systems. In one preferredembodiment of the present invention, the polishing pad conditioner ofthe present invention may be employed in a chemical mechanical polishingsystem with multiple polishing pads. FIG. 5 illustrates a chemicalmechanical polishing system with multiple polishing pads. The chemicalmechanical polishing system 500 includes a first polishing pad 510 and asecond polishing pad 520. A wafer 530 is fixed on the first polishingpad 510 through the back pad 540, motivated by the rotating back pad 540and undergoes the chemical mechanical polishing process in the presenceof the slurry 550. On the other hand, the polishing pad conditioner 560of the present invention conditions the second polishing pad 520 onwhich a wafer is absent. Or, on the contrary, the wafer 530 is fixed onthe second polishing pad 520 through the back pad 540 and undergoes thechemical mechanical polishing process in the presence of the slurry 550.On the other hand, the polishing pad conditioner 560 of the presentinvention conditions the surface of the first polishing pad 510 on whicha wafer is absent. By doing so, the polishing pad conditioner of thepresent invention may clean the slurry, particles or crystals on thesurface of the dressing component of the polishing pad conditioner andconditions the surface of the polishing pad through the cleaned dressingcomponent.

Or, in another preferred embodiment of the present invention, thepolishing pad conditioner of the present invention may be employed in achemical mechanical polishing system with a single large-sized polishingpad. FIG. 6 illustrates a chemical mechanical polishing system with asingle large-sized polishing pad. The chemical mechanical polishingsystem 600 includes a rotary polishing pad 610. At least one wafer 620is fixed on the polishing pad 610 through the back pad 630, motivated bythe rotating back pad 630 and undergoes a chemical mechanical polishingprocess. Simultaneously, the polishing pad conditioner 640 of thepresent invention conditions the surface of the polishing pad 610 onanother site. Moreover, the polishing pad conditioner of the presentinvention may be employed in a linear chemical mechanical polishingsystem, as shown in FIG. 7. The linear chemical mechanical polishingsystem 700 includes a polishing pad 710. A wafer 720 fixed by the backpad 630 and motivated by the rotating back pad 630 undergoes thechemical mechanical polishing process. On the other hand, the polishingpad conditioner 740 of the present invention conditions the surface ofthe first polishing pad 710 on another side. By doing so, the polishingpad conditioner of the present invention may clean the slurry, particlesor crystals on the surface of the dressing component of the polishingpad conditioner and conditions the surface of the polishing pad throughthe cleaned dressing component.

EXAMPLE

The following example provides a comparison between the polishing padconditioner of the present invention and the conventional polishing padconditioner.

The polishing pad conditioner of the present invention and theconventional polishing pad conditioner are operated in a WCMP-5 systemunder identical recipes to compare the removal rate uniformity (RR_U %).The polishing pad conditioner of the present invention was operated for8 working days. The conventional polishing pad conditioner was operatedfor 111 working days.

Conventional polishing pad conditioner

Conventional polishing pad conditioner RR_U % 1 6.4839 2 6.785 3 6.03434 8.093 5 8.3594 6 8.8052 7 6.056 8 7.4234 9 14.0378 10  5.4041 11 6.4756 Average 7.6325

Polishing pad conditioner of the present invention:

Polishing pad conditioner of the present invention RR_U % 1 5.7648 26.4487 3 6.9301 4 5.0689 5 4.4262 6 5.8628 7 5.2237 8 6.1312 Average5.7320

The comparison results clearly show that the novel polishing padconditioner of the present invention indeed efficiently diminish thedefects of the wafer during the chemical mechanical polishing process.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention.

1. A polishing pad conditioner for chemical mechanical polishing,comprising: a dressing component for conditioning a pad; and a housingcomprising at least one fluid hole surrounding said dressing componentfor providing at least one fluid for accommodating said dressingcomponent.
 2. The polishing pad conditioner for chemical mechanicalpolishing of claim 1, wherein said dressing component is round.
 3. Thepolishing pad conditioner for chemical mechanical polishing of claim 2,wherein said housing comprises a plurality of parts.
 4. The polishingpad conditioner for chemical mechanical polishing of claim 1, whereinsaid dressing component is selected from a shape of a polygon consistingof triangle and rectangular.
 5. The polishing pad conditioner forchemical mechanical polishing of claim 1, wherein said housing comprisesa slot for engaging with said dressing component to fix a relationposition between said dressing component and said housing.
 6. Thepolishing pad conditioner for chemical mechanical polishing of claim 1,wherein said fluid is selected from a group consisting of water andslurry.
 7. The polishing pad conditioner for chemical mechanicalpolishing of claim 1, wherein said fluid substantially contacts saiddressing component when spurting from said fluid hole.
 8. The polishingpad conditioner for chemical mechanical polishing of claim 1, furthercomprising at least one screw to fix a relation position between saiddressing component and said housing.
 9. A polishing pad conditioner forchemical mechanical polishing, comprising: a dressing component forconditioning a pad; and a housing for accommodating said dressingcomponent, said housing comprising at least one fluid hole surroundingsaid dressing component for providing at least one fluid and a slot forengaging with said dressing component to fix a relation position betweensaid dressing component and said housing.
 10. The polishing padconditioner for chemical mechanical polishing of claim 9, wherein saiddressing component is round.
 11. The polishing pad conditioner forchemical mechanical polishing of claim 10, wherein said housingcomprises a plurality of parts.
 12. The polishing pad conditioner forchemical mechanical polishing of claim 9, wherein said dressingcomponent is selected from a shape of a polygon consisting of triangleand rectangular.
 13. The polishing pad conditioner for chemicalmechanical polishing of claim 9, wherein said fluid is selected from agroup consisting of water and slurry.
 14. The polishing pad conditionerfor chemical mechanical polishing of claim 9, wherein said fluidsubstantially contacts said dressing component when spurting from saidfluid hole.
 15. The polishing pad conditioner for chemical mechanicalpolishing of claim 9, further comprising at least one screw to fix arelation position between said dressing component and said housing. 16.A method for polishing a substrate, comprising: providing a substrate;and polishing said substrate with a polishing tool, wherein saidpolishing tool is provided with at least a polishing pad and at least apolishing pad conditioner, and said polishing pad conditioner includes adressing component for conditioning a pad and a housing foraccommodating said dressing component, and said housing includes atleast one fluid hole surrounding said dressing component for providingat least a fluid.
 17. The method of claim 16, wherein said dressingcomponent is round.
 18. The method of claim 17, wherein said housingcomprises a plurality of parts.
 19. The method of claim 16, wherein saiddressing component is selected from a shape of a polygon consisting oftriangle and rectangular.
 20. The method of claim 16, wherein saidhousing comprises a slot for engaging with said dressing component tofix a relation position between said dressing component and saidhousing.
 21. The method of claim 16, wherein said fluid is selected froma group consisting of water and slurry.
 22. The method of claim 16,wherein said fluid substantially contacts said dressing component whenspurting from said fluid hole.
 23. The polishing pad conditioner forchemical mechanical polishing of claim 16, further comprising at leastone screw to fix a relation position between said dressing component andsaid housing.